Add instructions for one release or more

Author: d9beuD

README.md

@@ -19,6 +19,11 @@ https://www.monstercat.com/release/MCEP157
 We just need the release ID, in this case: `MCEP157`.
 Download all songs in this release with this simple command:
 
+```bash
+php monstercat-dl.php MCEP157
+```
+
+You can download more songs at once by adding other release IDs at the end of the command:
 ```bash
 php monstercat-dl.php MCEP157 MCX006 MCS778
 ```